Maryland has awarded five slots licenses, but the bidding process for the sixth gambling establishment, in Prince George’s County, could be more protracted and competitive when it gets under way next week.

The process for bidding for the state’s sixth casino license, which voters authorized via referendum in November, opens Thursday.

MGM Resorts International of Las Vegas intends to bid. Penn National Gaming, the Wyomissing, Pa., owner of Hollywood Casino Perryville, is considering a bid. The two companies ponied up the lion’s share of the $93 million spent on the referendum campaign: MGM backed the measure, while Penn National, owner of Rosecroft Raceway in Fort Washington, opposed it, saying the deck was stacked in MGM’s favor.

Through the referendum — still the subject of a lawsuit — voters OK’d a Prince George’s casino, plus adding table games such as poker to all slots parlors and allowing them to operate round-the-clock.

MGM has proposed building a $800 million casino at National Harbor in Oxon Hill, while Penn National wants to bring slots and table games to Rosecroft.

The dueling interests could require a thorough review of at least two bids, said Donald C. Fry, chairman of the state’s seven-member Video Lottery Facility Location Commission. Other licenses have had multiple bidders, he said, but rival bids were disqualified quickly due to lack of funding or other criteria.

“This may be a different dynamic, but I don’t think it will change the process,” said Fry, president and CEO of the Greater Baltimore Committee.

Current slots locations are the Hollywood Casino, the Casino at Ocean Downs in Berlin and Maryland Live! Casino in Hanover. Licensed and slated to open are Caesars Entertainment’s Horseshoe Baltimore Casino and a casino at Rocky Gap Lodge and Resort in McHenry.

All license bidders and key people involved in the proposals must undergo a thorough investigation of their personal, financial and criminal backgrounds, Fry said. Previous investigations have taken up to eight months; the length of time depends on how many people are involved in a proposal and whether bidders have been involved in recent bids. License owners must be able to provide a license fee of $3 million per 500 slot machines.

Fry said licensing decisions are decided primarily — 75 percent — on market factors, with 15 percent based on economic development potential and 15 percent on location. Bidders have until the end of May to submit proposals.

“The ultimate decision is as to what’s in the best interest of the state of Maryland,” he said. “We have a pretty prescriptive process set for us in the statute. The commission works to consider all factors and ensure a proposal produces a facility that we can be proud of.”

MGM is confident.

“MGM Resorts remains enthusiastic about the opportunity in Maryland, and we look forward to the state’s release of the (request for proposal) for the Prince George’s license,” Gordon Absher, vice president of public affairs for MGM wrote in an email to The Gazette.

“Based on our experience and the strength of our brands, combined with the location and infrastructure at National Harbor, we feel we’ll be able to submit an attractive and highly competitive proposal,” Absher wrote.

Penn National did not have more details beyond an earlier statement that it was considering a bid, spokeswoman Karen Bailey wrote in an email to The Gazette.

State law prohibits a business from owning more than one slots license, which means Penn National might need to shed its Perryville license should it win one in Prince George’s. Penn National did not respond to a request for comment on this.

The bidding process also will involve public hearings and a contingency for Prince George’s to approve the proper zoning. Fry estimated a license might be awarded by the end of 2013, although having two bidders could delay the award.

The Prince George’s casino cannot begin operating before July 1, 2016, or 30 months after the casino in Baltimore city is open, according to state law. A license owner, however, could request to operate table games in a temporary facility upon winning a license.